Direct action air compressor and muffler



Nov. 9, 1937. J. R. TUCKER 2,098,474

DIRECTACTION AIR COMPRESSOR AND MUFFLER 'Filed may 22, 1955 INVENTOR BY* JOI/IV l?. 70E/(ER @and 8%@ Patented Nov. 9, 1937 UNITED STATES PATENT OFFICE nilmc'r Ac'rroN' Am COMPRESSOR. AND MUFFLER 18 Claims.

This invention relates to means for and a method of compressing gaseous fluids, and more particularly to compressors of the rotary type in which a rotor is driven by a compressed uid and is caused to compress another fluid. While the invention is susceptible of use in various relations, it is my belief that, at the present time, its greatest eld of utility is in the art of internal combustion engines, particularly Diesel engines,

in which the exhaust gases of the engine form the operating or compressor fluid while the compressed iluid is used for scavenging the vengine cylinder and for supporting combustion in such cylinder. To support combustion, the compressed fluid must contain the proper amount of oxygen,

and it is most convenient and economical to use air.

It is an object of the invention therefore, to provide a novel form of compressor and method in which a fluid under pressure, such as the exhaust gases from an internal combustion engine, is caused to compress another gaseous fluid and to deliver the same in such a manner and at such a pressure as to render it available for use. More particularly, it is an object to compress atmospheric air and make it adaptable for use in scavenging the cylinder or cylinders of an internal combustion engine and for supporting combustion therein. Hereinafter, the rstmentioned iluid will be designated the compressor uid and the other the compressed fluid.

Still more particularly stated, an object of the invention is to produce a iluid compressor in which a varied rotor, in a casing, is driven by impact and reaction of the compressor iiuid against the' rotor vanes to turn the rotor, the rotation of the latter causing another fluid to enter the compressor casing and there be compressed by direct action of the compressor fluid 40 thereon, the said other fluid then being discharged from the casing and conducted to a point or points for use. It is a further object to cause the rotor to be driven at such a high speed that the two iiuids will remain in contact within the casing for such a short period of time as sub* stantially to prevent them from intermingling and assure a discharged compressed fluid which carries Alittle if any impurities.

AS is well known, the exhaust gases from an internal combustion engine are discharged at a high temperature and a'relatively high pressure.

This pressure and temperature above the atmospheric represent energy which not only is lost but which manifests itself in the heat and noise of the exhaust. The heat thus lost is a positive Waste of energy, while the noise is a nuisance which requires the use of some kind of mufliing device for its suppression. It is an 'object of my invention to eliminate the usual muler and rely upon the compressor for dead- 5 ening the noise of the exhaust. When, therefore, my compressor is driven by the exhaust gases from an internal combustion engine, the gases are forced between the vanes of the rotor and are conducted in such a course through the 10 casing that they give up much of their energy in doing useful work, finally issuing from the casing with but little noise. Moreover, While the compressor is an eiiicient mufller, it produces but little back-pressure. l5

The above and other features and advantages of my invention will be set forth more at length and in greater detail in the following description of what is, at present, my preferred ernbodiment of the invention, it being understood 20 that that particular embodiment is shown for illustrative purposes only.

1n the drawing, Fig. l is a vertical cross-sectional view of my invention taken on the plane represented by line I-I of Fig. 2 and illustrated 25 as applied to the crank shaft of an internal combustion engine; Fig. 2 is a side elevation, on a reduced scale, of the invention, looking toward the right in Fig. l; Fig. 3 is a cross-sectional view, on an enlarged scale, taken on line 3-3 30 of Fig. 2; Fig. 4 is a perspective View of one of the longer rotor vanes, and Figs, 5 and 6 are crosS-' sectional views on the lines 5 5 and 6 6, respectively, of Fig. 2.

Describing the invention more in detail by 35 reference to the drawing, l0 represents the end of a shaft, which may be and usually is the rotating crank-Shaft of an internal combustion engine. In some engines, however, this shaft is non-rotatable and the cylinders revolve about it. 40 The end of the Shaft is journaled or mounted within a member Il, which may be an integral part of the engine frame or may be rigidly attached thereto. This member is a part of the compressor casing, the other part, f2, of which 45 is secured to the part Il in any suitable manner, as by bolts I3. The casing is thus divided on a plane which is perpendicular to the shaft I0, said plane being so positioned that the space Within the casing is substantially half within the 50 part Il and half within the part l2. In axial alinernent with the shaft I0 is a short stub-shaft I4 upon which the rotor, hereinafter described, is mounted. As shown, the stub-shaft is threaded within the end of the shaft I0 so as to rotate 55 therewith if the latter shaft turns. If the shaft lil is non-rotatable, the stub-shaft will likewise be non-rotatable. In fact, it is not necessary that it be connected with the shaft so long as it is rigidly supported at the axial center of the compressor casing. However, the shaft provides such a rigid support and it is preferred.

Mounted upon the stub-shaft it are roller bearings l and it for the rotor, the latter having a disk-like side member ll and a hub-like extension HB, within which member and extension the outer races of the rotor bearings are mounted. The outer end of the hub extension is closed by a hub-cap i9. The side member il and the extension it meet'or merge in a. curve and, on their surfacesA within the rotor chamber they are provided with a series of shallow grooves'wlthin which the edges of the rotor vanes or, blades are rigidly secured. As shown in Fig. 2, these vanes extend radially as respects the rotor axis and they preferably have their outer ends curved, asv at 2d. Opposite the member il of the rotor and substantially contacting the inner wall of the casing member 'l2 is an annulus 2l, the same being broken away in part in Fig. 2 better to show thefvanes. This annulus also has the radial .grooves within which the edges of the vanes are rigidly secured. IThe vanes thus provide rigid connections between. the rotor member lll and the annulus and compel them to turn' together. Preferably, half of the vanes are U-shaped, as shown in Fig. 4, these vanes being designated 22. They are bent laterally at 2li and have their outer edges secured to the members il and 2 l, as stated. The casing part i2 is curved inwardly at 2t to conform to the outer curved portions of these vanes, the inner curved portions of which iit into the grooves of the hub it. The curved part 23 of the casing member i 2 extends substantially half-way across the rotor chamber and its inner edge ts snugly aboutk the hub i8, forming a substantially air-tight joint therewith. Midway across the r'otor chamber and between the legs of the U-shaped vanes is a rotor annulus 24. 'This annulus is grooved on both of its sides to receive the inner edges of the said legs, which edges are rigidly secured within the grooves. The annulus extends inwardly to the bottoms of the spaces between the legs, and outwardly beyond the outer ends Aof the legs where it is conned between the casing members Il and l 2, grooves or rabbets being formed in said members to receive the annulus with a substantially uuid-tight fit to prevent leakage about its outer edge. As will be seen from this description, the' rotor is a very rigid structure. But' it is made still more rigid by the other vanes 25 which alternate in position with the U-shaped vanes 22. These vanes 25 would be identical with the U-shaped'vanes if the latter were cut oil at the inner ends of the legs, as on the dotted lines 26 of Figs. 1 and 4. In other words, the vanes 25 have a length equal only to the radial width of the annulus 2|. The vanes 25 have their side edges confined ingrooves 1n the rotor member I1 and 'in the annuli 2l and 24, being rigidly secured therein. As will be noted from Fig. 2, the casing extends llt-little more than half way about the rotor, the same terminating at the planeslrepresented by the lines 2l and 28 respectively.`v Between and to the right of these planes the rotor vanes are enclosed within a tun.1 iel-like chamber or passage, the cross-sectional shape of which is shown inria. i. Between and. to the left or said planear the rotor vanes are not enclosed but arei'reely open to the air. The vpurpose of this structure will presently be explained.

2@ is a pipe which may leadfrom the exhaust manifold of an internal combustion engine or from any other suitable source vof compressed uid, said pipe being connected, as by threading, to the member i 2 of the rotor casing. This pipe discharges its compressed uid directly into a passage 30 in said member l2 outside the perimeter of the rotor, the casing member being shown as broken away in part/in Fig. 2 to reveal the said passage and other features of the structure. Surrounding the end of the pipe 2t and for a short distance inwardly therefrom the wall of the passage is continuous to form what may be termed a seal for the outer ends of the rotor vanes, said seal ending at 3i. Between the point 3l and the plane 2l the vanes extend outwardly to the casing member, as shown in Fig. l, and form a substantially uid-tight contact therewith. The seal preferably subtends some three or four of the vanes so as to prevent any leakage of the compressor fluid backwardly. The passage d@ extends approximately half-way about the perimeter of the rotor and is in open communication with the rotor chamber from the edge 3l of the seal to the'point 32 where the passage terminates. Throughout this communicating portion of the passage, its outer wall gradually approaches the rotor so that all fluid therein is compelled sooner or later to enter between the left-hand rotor vanes, as viewed in ligl. This narrowing of the passage in a radial direction is indicated in Figs. 3 and 5. The passage im may be termed the intakepassage for the compressor fluid.

In the casing member ll outside the vanes and parallel to the passage 30 is a similar passage 33 which is in open communication with the spaces between the right-hand rotor vanes Ifrom a point indicated in dotted lines at 34 to the edge of a seal which is indicated in dotted lines at 34'. The passage 33 gradually increases in radial width from the point 34 until it reaches the'seal at 34', beyond which its wall is continuous, as shown lat the bottom of Fig. 2. A pipe 35 is secured within the outer end of the passage to conduct away the uid which enters the passage from the rotor vanes.

Although, as stated, my compressor Ymay be used in various other relations, for purposes of description of the operation it will bey assumed that the pipe 29 is connected with the exhaust manifold of a two-cycle internal combustion engine of the Diesel type. As is well understood, upon the opening of the exhaust port, the burned gases escape, partly by reason of their own expansibility-and partly by being blown out of the cylinder by the scavenging action of the incoming air which enters through the intake manifold almost instantly after the exhaust begins. 'This air lls the cylinder andvis compressed during the compression stroke ready to receive an injection of fuel'. The pipe 29 receives the exhaust.

gasswhile the fresh air for the intake manifold of the engine is furnished by the compressor through the pipe 35, the air being obtained and compressed in the manner now to be described.

The exhaust` gases enter the passage 30 under crowd the air into the air passage 33.

the gases enter farther and farther into the passage, they are crowded inwardly into the pockets between the vanes and by ,expansion and reaction supply an additional impulse in turning the rotor. Beyond the point 32 the exhaust gases are all coniined within the spaces or pockets between the rotor vanes and are swept out of the casing at the plane of the line 28. By this time the rotor is turning rapidly and the exhaust gases are flung outwardly into the air. In the meanwhile, the pockets between the vanes which areentering the casing at the plane of the line 21 are filledl with air and those pockets which are subtended by the seal between 21 and 3| contain nothing b ut air. Such is the condition present at the upperpart of Fig. 1. As soon as one-of these pockets passes the point 3l, the exhaust strikes the forward vane and enters the pocket between the annuli 2| and 24 on top of the air, thus compressing the air below it and within the space between the annulus 24 and the member I1. As soon as the vanes reach the end of the passage 33 at the point 34 this cornpressed air begins to flow into the passage 33; and as the rotor turns the exhaust gases ll more and more completely the rotor-vane pockets and The compressor is designed for high speed and the parts are so proportioned that the cut-oir into the air passage at the lower seal is reached before all of the air has been expelled from the pockets, so that substantially nothing but the compressed air enters the pipe 35. by reason of the high speed, the exhaust gases and air have no time to intermingle or, if any intermingling takes place, it is in that part of the air which is cut oif and which is expelled with the exhaust gases.

While all the vanes may be U-shaped, as in Fig. 4, I prefer to alternate these vanes rwith the shorter ones 25 in order to provide more ample spaces for the air to flow into the pockets between the rotor vanes. The air passage 33 or the pipe 35, if preferred, may be provided with a valve 31 for controlling the air passing to the cylinder. At times, as when the engine is starting or is running slowly, there will be but a relatively small supply of the exhaust or compressor gases and the rotor will be driven at a correspondingly slow speed. That means that the said gases will remain in contact with the air within the rotor for a longer time and will, to an objectionable degree, commingle with it. If at that time the valve 31 be fully open the air passing to the engine will be yimpure and will not properly support combustion. By partially closing the valve, the pressure within the compressor is increased and the flow of air into the passage 33 will be cut oii' before the impure gases can reach the latter. Thus can pure air be assured for "scavenging the engine cylinder and for combustion even when the engine is starting or is running slowly. Of course the compressed 1 air may be caused to pass through the carburetor of a two-cycle vor a four-cycle engine thus to obtain th mixture necessary for .an explosive charge.

As is clear from Fig. 1, the exhaust gases entering the compressor casing at the top are forced to pass downwardly between the vanes at the left, to the right around the annulus 24 and up at the right to compress the air. Before they can 'reach the upper ends of the vanes at the right they are released to the open air at the plane 28 of Fig. 2 and are flung centrifugally Moreover,

they release their contained gases. The pressure of these gases has been greatly reduced and the quantity in each 4pocket is so small that the escape of these small amounts of gas produces a sound in the nature of a hiss or low hum which has none of the objectionable features of the usual exhaust.l Moreover, the air taken.

into the compressor cools the casing, as is obvious. While I have thus disclosed what is at present my preferred form of compressor and its mode of operation,`it is obvious that the details shown and described may be modified without .departure from the spirit of the invention and it is to be understood that the following claims are not intended to be limited to such details any further than is'necessitated by their terms and by the state of the prior art.

Having thus described my invention, I claim:

1. An air compressor comprising a casing having a rotor chamber therein, said chamber extending about within the casing in an arc of a circle and being open to the outside air at its ends, a rotor mounted to rotate about an axis at the center of curvature of the said chamber, said rotor being partially within the chamber and partially in the open air outside the casing, vanes carried by and rigidly attached to the rotor, said vanes when within the casing forming with the casing aseries of pockets, the spaces between the vanes being filled with air while the vanes are outside the casing, said casing having a pair of uid passages extending about the chamber and in open communication therewith and with the pockets therein, means through which a fluid under pressure is 'admitted to one of said passages and, through it, to the said chamber to enter one part of the tact with the air within said pockets, thus to compress said air and force :it 'toward and into the other passage in the casing, and means for cutting off the communication between the pockets and the said other passage before all the air has been forced fromthe pockets and before substantially any of the pressure fluid has reached the second passage.

2. An air compressorA as 'set forth in claim 1 in which the vanes are U-shaped in contour with the legs of the U extended outwardly and in which the fluid under pressure is admitted to the pockets at the end of one of the legs and is discharged from the pockets at the end of the other leg, and a -partition member separating the legs of the vanes, thus forming U-shaped pockets within which` the airis compressed.

3. An air compressor asset forth in claim 1 in' which 'the passage for the fluid under pres` slne is sealed from the pockets within the casing at the end of the arcuate chamber where the vanes enter the casing and in which the said other passage is sealed from the pockets at the end of the chamber where the vanes emerge from it, for the purpose speciiied.

4. An air compressor as set forth in claim 1 in which the alternate vanes are U-shaped and the intervening vanes are short and are terminated atmen inner ends on a circular une 7swhich is coincident with the inner ends of the legs of the U-shapedlvanes.

5. An air compressor as set forth in claim ll in which the alternate vanes are U-shaped while the intervening vanes are short and are terminated at their inner ends on a circular plane which is coincident with the inner ends of the legs of the U-shaped vanes and in which the outer ends of the vanes are bent backwardly with respect to the direction Iof rotation of the rotor, for the purpose specified.

6. An air compressor as set forth in claim ll in which the casing is divided transversely by the axis of rotation between the two fluid passages in the casing and through the rotor chamber, whereby one of the said passages is within one part of the casing and the other passage is within the other part of the casing, and means for detachably connecting said two parts together.

'7. An air compressor having a rotor comprising a disk-like side member, a central hub projecting from said side member, an outer annulns spaced from said member and coaxial therewith but spaced from said hub, a central annulus substantially 'midway between the side member and the said outer annulus, said central annulus being likewise spaced from the hub, and a plurality of spaced U-shaped vanes having outwardly-directed legs secured at their side edges to the member and the two annuli, the curved portions of the Vanes being secured to the hub, whereby all the parts of the rotor are rigidly secured together, a two-part casing divided in substantially the plane of the central annulus and shaped to define a chamber for the rotor,

one wall of the chamber being on one part of the casing and fitting against the outer side of the disk-like member and the oppoL e wall of the chamber being on the other parll of the casing i and tting against the outer wall of the outer annulus, said opposite wall being curved to fit the curve of the U-shaped members and terminating at the hub about which the said other part of the casing fits, the said other part of the casing and the rotor chamber extending in an arc of a circle but part way about the hub whereby but part of the vanes are at .any one time within the casing while the other vanes are exposed to the air, means 'leading to one of the'parts of the casing for conducting thereto a compressor fluid, said means communicating with a fluid passage in that part of the casing, said passage extending about the rotor chamber and being open thereto so that the compressor uid may enter said chamber and between the outer legs of the U-shaped vane, means leading from the other part of the casing for-con ducting away the air which is compressed in the compressor, said latter means communicating with an air passage in said other part of the casing, said air passage extending about the rotor chamber and in open communication therewith-so that the air compressed between the inner legs of the U-shaped vanes can pass into said air passage and be led away through the said conducting means,` the air between the vanes being compressed by the direct action of the compressor fluid i.hr er,eon.

8. An air compressor asset having a valve for controlling the flow of the compressed air from the compressor.

9. vAn air compressor as set forthin 'claim 'l in which the central annulus is extended out-'- wardly beyond the legs of the vanes and between andere the two parts of the casing to prevent leakage of uid.

l0. An air compressor as set forth in claim. 'l in which the passage in the casing which receives the compressor fluid gradually decreases in its radial dimension as it extends about the rotor chamber in the direction of rotation of the rotor whereby the compressor fluid is forced into said. chamber against and between the vanes of the rotor.

11. An air compressor as set forth in claim 7 in which the passage in the casing which receives the compressor. uid gradually decreases in its radial dimension as it extends about the rotor chamber in the direction of rotation of the rotor and in which the air passage in the casing gradu ally increases in its radial dimension as it extends about the rotor chamber in the same direction, for the purpose specified. l

,12.- In combination, a casing for a combined air compressor and muiller, said casing having a rotor chamber therein, a pipe for the exhaust gases from an internal combustion engine leading to and connected with said'casing, a pipe for compressed air connected with and leading from said casing and adapted to be connected with the intake manifold of said engine, a rotor having vanes thereon rotatable within said casing,A said casing being cut away at the ends of said rotor chamber to expose the vanes to the open air whereby the spaces between the vanes become filled with air which is inducted into the casing as the rotor vanes enter said chamber, means whereby the said exhaust gases are caused to impact against said vanes and to enter the spaces between the latter in direct contact with the air in said spaces whereby the rotor is turned and the airis compressed, and means within the casing for receiving the compressed air and for conducting it to the said pipe for compressed air, the passage for the exhaust gases through the casing being such that the compressor serves to mume the exhaust.

13. A device for obtaining compressed air for use in supporting combustion in an internal combuston engine comprising a 'casing having a chamber therein and the chamber having an inlet and 'a discharge port openingthereinto throughv the casing, means connected with the casing and adapted for connection with the exhaust of said engine for leading the exhaust gases under pressure to the said inlet port of the chamber, means connected with said casing, and adapted for connection with the intake manifold of said engine, said latter means being adapted to conduct compressed air from the casing to said manifold, a member movable within said casing and having a series ofpockets therein, means on said :member4 for coaction with the exhaust gases to move the said member to bring the pockets in succession into communication with the inlet and discharge ports of the casingeach of said pockets having a pair of spaced openings and the casing having an extended opening through which atmospheric air may be admitted into the pockets to ll the latter with air, means on the casing' for closing the openings of the pockets as the member is moved from the opening in the casing, said pockets then being adapted for further movement to bring their spaced openings into communication with the inlet and discharge ports of the casing, the construction being such that the exhaust gases are admitted through one of the' said openings of the pockets intggdirect contact with the air therein to compress thsaid air and force it 75.

toward the said other opening, and means to close the said other opening before all the air has escaped from the pocket, the escaped air passing into the means which communicate with the intake manifold of the engine.

14. A device as set forth in claim 13 in which the casing is provided with a centrally-positioned shaft and in which the movable member is a vaned rotor rotatable with respect to said shaft.

15. A device as set forth in claim 13 in which the means communicating with the casing and the intake, manifold is provided with a valve whereby the degree of pressure of the air in the pockets maybe varied, for the purpose speciiied.

16. An air compressor 'comprising a casing having a chamber therein, a rotor rotatable within said chamber, vanes carried by and rigidly attached to said rotor, said vanes being exposed to the air without the casing when they are turning through a part of their rotation and being sealed from the outside air through the remainder of their rotation, said vanes when thus sealed forming with the casing a series of rotor pockets, said casing having a pair of fluid passages leading to said chamber, one of said passages extending about the chamber and in open communication therewith and with the rotor pockets, means through which a iiuid under pressure is admitted to one of said passages and, through it, to the said chamber to enter one part'of the pockets within the chamber and into direct contact with the air within said pockets, thus to compress said air and force it toward and into the passage which extends about the chamber, and means for cutting 011' the communication between the pockets. and the last mentioned passage before all the air has been forced from the pockets.

17. In combination, an air compressor casing, a pipe for the exhaust gases from an internal combustion engine leading to and connected with said casing, a pipe for compressed air connected to and leading from said casing, a rotor within said casing, said rotor having vanes thereon which cooperate with the interior of the casing to form a series of pockets, the casing being so constructed as to expose the pockets to the outside air during a portion of the rotation of the rotor, whereby the exposed pockets become filled with air, and to seal the pockets against the outside air throughout the remaining portion of said rotation, means for causing the exhaust gases to impinge against the rotor vanes to turn the rotor and to enter the pockets at one part thereof into direct contact with the air therein, whereby the air is 'dompressed and is forced away from the point of entry of the said gases toward a remote part of the pockets and into the pipe for the compressed air, and means for'cutting oi the passage into said compressed air pipe before all the air has been forced from the pockets.

18. An air compressor-'as set forth in claim 17 in which the said compressed air pipe is provided with means to modify the freedom of passage of the compressed air whereby to vary the degree of pressureoi the air Within the compressor.

JOHN R. TUCKER. 

